Connect any Plantronics H-series CORDED headset to a phone with a standard, round 2.5mm headset jack with this connector cable. This 18" long cord has a 2.5mm plug prong at one end and a QuickDisconnect at the other end. Compatible with Polycom IP 320, 321, 330, 331, Zultys ZIP 4x4 and ZIP 4x5, Panasonic, AT&T, RCA desk phones, most cordless phones and any other phone with a 2.5mm headset jack.